Logic script

Class hierarchy
CLogicScript ↳CPointEntity ↳CBaseEntity

logic_script is a point entity available in all Source games since Left 4 Dead 2. It is also available in Team Fortress 2 and Mapbase and it is the container for VScripts. In Left 4 Dead 2, for example, this entity is used extensively for the logic in "carnival games" found in the Dark Carnival campaign, such as Peanut Gallery, Strongman Contest, Whack-a-Stach, etc.

KeyValues

Name (targetname) <string>[ Edit ]

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also:  Generic Keyvalues, Inputs and Outputs available to all entities

EntityGroup[0] (Group00) to EntityGroup[15] (Group15) <targetname>

All specified entity names will be searched for upon this entity spawning and their script handles are added to an array named EntityGroup in logic_script's script scope. EntityGroup[0] contains handle of entity with name specified in EntityGroup[0] property etc. If multiple entities with the given named exists, handle of first found will be used.

Table MyEntityGroup is also created which contains the handles with keys being the names. (for some reason there is also MyEntityGroupArray which is same as EntityGroup)

Vscript run internally to achieve this

The following vscript is run in logic_script scope when it spawns. __AppendToScriptGroup is then called with each name specified by Group00-Group15 keyvalues. EntityGroup <- []; MyEntityGroup <- {}; MyEntityGroupArray <- EntityGroup; function __AppendToScriptGroup( name ) { if ( name.len() == 0 ) { EntityGroup.append( null ); } else { local ent = Entities.FindByName( null, name ); EntityGroup.append( ent ); if ( ent != null ) { ent.ValidateScriptScope(); MyEntityGroup[name] <- ent; ent.GetScriptScope().EntityGroup <- EntityGroup; } } }

Entity Scripts (vscripts) <scriptlist> (in all games since )

Space delimited list of VScript files (without file extension) that are executed after all entities have spawned. The scripts are all executed in the same script scope, later ones overwriting any identical variables and functions.

Think function (thinkfunction) <string> (in all games since )

Name of the function within this entity's script that'll be called automatically every 100 milliseconds, or a user-defined interval if the function returns a number. Avoid expensive operations in this function, as it may cause performance problems.

Inputs

RunScriptFile <scriptRedirectInput/string> (in all games since ) (also in )

Execute a VScript file from disk, without file extension. The script contents are merged with the script scope of the receiving entity.

RunScriptCode <stringRedirectInput/string> (in all games since ) (also in )

Execute a string of VScript source code in the scope of the entity receiving the input. String quotation may be needed when fired via console.

Bug:In Hammer, using string arguments will corrupt the VMF file's structure, making the file unviewable for the next Hammer session.

Fix:Remove the string argument manually with a text editor.

  [todo tested in ?]

Note: Backtick characters ` are replaced with quotation marks at runtime, allowing quotation marks to be used when normally not possible.

CallScriptFunction <stringRedirectInput/string> (in all games since ) (also in ) !FGD

Calls a VScript function defined in the scope of the receiving entity.

TerminateScriptScope  (only in ) !FGD

Destroys the script scope of the receving entity.

See also

• L4D2 Vscripts
• Left 4 Dead 2 Tool Updates

External links

• It's the vscripting documentation FAQ! (Steam Forums)
• Scripting for Left 4 Dead 2 (Leeland.net) - Example uses of logic_script